Intelligent and Secure Radio Environments for 6G Vehicular Aided HetNets: Key Opportunities and Challenges

in IEEE Communications standards Magazine (2022)

Reconfigurable meta-surfaces are emerging as a novel and revolutionizing technology to enable intelligent wireless environments. Due to the low cost, improved efficiency, and passive nature of reflecting ... [more ▼]

Reconfigurable meta-surfaces are emerging as a novel and revolutionizing technology to enable intelligent wireless environments. Due to the low cost, improved efficiency, and passive nature of reflecting elements, it is becoming possible to program and control the wireless environment. Since wireless physical layer technologies can generally adapt to the wireless environment, their combination with reconfigurable surfaces and deep learning approaches can open new avenues for achieving secure 6G vehicular aided heterogeneous networks (HetNets). Motivated by these appealing advantages, this work provides an intelligent and secure radio environment (ISRE) paradigm for 6G vehicular aided HetNets. We present an overview of enabling technologies for ISRE-based 6G vehicular aided HetNets. We discuss features, design goals, and applications of such networks. Next, we outline new opportunities provided by ISRE-based 6G vehicular HetNets and we present a case study using the contextual bandit approach in terms of best IRS for secure communications. Finally, we discuss some future research opportunities. [less ▲]

Functional observability and subspace reconstruction in nonlinear systems

in Physical Review Research (2022), 4

Time-series analysis is fundamental for modeling and predicting dynamical behaviors from time- ordered data, with applications in many disciplines such as physics, biology, finance, and engineering ... [more ▼]

Time-series analysis is fundamental for modeling and predicting dynamical behaviors from time- ordered data, with applications in many disciplines such as physics, biology, finance, and engineering. Measured time-series data, however, are often low dimensional or even univariate, thus requiring embedding methods to reconstruct the original system’s state space. The observability of a system establishes fundamental conditions under which such reconstruction is possible. However, complete observability is too restrictive in applications where reconstructing the entire state space is not necessary and only a specific subspace is relevant. Here, we establish the theoretic condition to reconstruct a nonlinear functional of state variables from measurement processes, generalizing the concept of functional observability to nonlinear systems. When the functional observability condition holds, we show how to construct a map from the embedding space to the desired functional of state variables, characterizing the quality of such reconstruction. The theoretical results are then illustrated numerically using chaotic systems with contrasting observability properties. By exploring the presence of functionally unobservable regions in embedded attractors, we also apply our theory for the early warning of seizure-like events in simulated and empirical data. The studies demonstrate that the proposed functional observability condition can be assessed a priori to guide time-series analysis and experimental design for the dynamical characterization of complex systems. [less ▲]

Corporate Managers, Price Noise and the Investment Factor

in Financial Innovation (2022), 8(61),

Préservation et distorsion : l’espace-temps des réseaux socio-numériques et du web archivé

in Revue d'Histoire Culturelle (2022), (5),

Massive data, also known as Big Data - originating from websites and digital social networks, in the form of text, images, videos or metadata -, constitute significant sources for recent and future ... [more ▼]

Massive data, also known as Big Data - originating from websites and digital social networks, in the form of text, images, videos or metadata -, constitute significant sources for recent and future research in cultural history. These “digital traces”, collected by researchers or institutions, require further methodological thoughts - from their archiving to their development, in order to analyse them at different scales (scalable reading). Indeed, they allow researchers to identify new spatiotemporal boundaries, but also asymmetries and distortions between the theoretical scope of Big Data (from the millisecond to the long term, from the meter to the globe) and its practical scope (regional inequalities in collection, noise and silences within the archives). Based on several research projects and institutional initiatives, this article aims at thinking about the space-time of born-digital heritage, from the standpoint of data, collections and research, in order to grasp both the consequences of this massive archiving on the shaping of history and the profession of historian, and to identify the ongoing issues of these historical sources for academic research. [less ▲]

Le CD-Rom, une histoire à graver

in Le Temps des Médias (2022), 39

This article looks back at the history of the CD-ROM in France by replacing it in the context of the development of optical disks in the 1980s-1990s. It enlightens the convergence between media and ... [more ▼]

This article looks back at the history of the CD-ROM in France by replacing it in the context of the development of optical disks in the 1980s-1990s. It enlightens the convergence between media and information technology and underlines its role as a missing link in the history of the digital, at a time of transition from Minitel to the Web. The CD-Rom has received less historiographical interest than other technological artefacts. Its multimedia character, the new forms of digital writing it induces, and the issues its use raised (piracy, copyright, etc.) remind us that the CD-Rom occupies a place in a history that goes beyond data and information storage. It also sheds light on the computerization and digitalization of both individual and professional practices in France. [less ▲]

Between marginal and mainstream. Communities and ecosystems at stake

in Internet Histories: Digital Technology, Culture and Society (2022)

The three research articles in this special issue and the interview with Ronda Hauben are partly the result of the 4th RESAW conference, that brought together through the RESAW network a community of ... [more ▼]

The three research articles in this special issue and the interview with Ronda Hauben are partly the result of the 4th RESAW conference, that brought together through the RESAW network a community of researchers, web archivists and professionals, united around a common interest, namely web history and web archives. The 4th RESAW conference, organised on 17 and 18 June 2021 by the C2DH (Centre for contemporary and digital history) at the University of Luxembourg, sought to examine the tension between marginal and mainstream in web history, and to go beyond this binary view. The aim was to study all the nuances, shifts in meaning, difficulties in defining and measuring audiences, as well as the evolution over the course of history of digital practices, content, producers, and communities, from the fringes and peripheries to the centre and the core of the Web. The RESAW conference was also an opportunity to launch the HIVI research project , hosted at the C2DH, and the topics that were addressed at the conference were also related to virality. [less ▲]

Cormenin et l’hystérisation de la joute parlementaire sous la monarchie de Juillet

in Savoirs en lien (2022), 1

Under the July Monarchy, parliamentary debate was marked by the sometimes unheard-of verbal violence of the exchanges that Louis de Cormenin, MP and pamphleteer, described in his Livre des orateurs (1836 ... [more ▼]

Under the July Monarchy, parliamentary debate was marked by the sometimes unheard-of verbal violence of the exchanges that Louis de Cormenin, MP and pamphleteer, described in his Livre des orateurs (1836). In the face of this hysterisation of parliamentary debate, did Cormenin plead for moderation? Did he advocate a debate that allowed room for verbal violence against the immobilism of ministerial policy? Or did he call for a middle way? This contribution seeks to answer this question in the light of the Livre des orateurs and the Lettres sur la liste civile. [less ▲]

Unsupervised network embedding beyond homophily

in Transactions on Machine Learning Research (2022)

Space-Terrestrial Cooperation Over Spatially Correlated Channels Relying on Imperfect Channel Estimates: Uplink Performance Analysis and Optimization

in IEEE Transactions on Communications (2022)

Agency of artificial intelligence tools in defining working conditions: Towards a research agenda on the individual employment contract

in Italian Labour Law e-Journal (2022)

Assessing the opportunity of combining state-of-the-art Android malware detectors

in Empirical Software Engineering (2022), 28

Research on Android malware detection based on Machine learning has been prolific in recent years. In this paper, we show, through a large-scale evaluation of four state-of-the-art approaches that their ... [more ▼]

Research on Android malware detection based on Machine learning has been prolific in recent years. In this paper, we show, through a large-scale evaluation of four state-of-the-art approaches that their achieved performance fluctuates when applied to different datasets. Combining existing approaches appears as an appealing method to stabilise performance. We therefore proceed to empirically investigate the effect of such combinations on the overall detection performance. In our study, we evaluated 22 methods to combine feature sets or predictions from the state-of-the-art approaches. Our results showed that no method has significantly enhanced the detection performance reported by the state-of-the-art malware detectors. Nevertheless, the performance achieved is on par with the best individual classifiers for all settings. Overall, we conduct extensive experiments on the opportunity to combine state-of-the-art detectors. Our main conclusion is that combining state-of-theart malware detectors leads to a stabilisation of the detection performance, and a research agenda on how they should be combined effectively is required to boost malware detection. All artefacts of our large-scale study (i.e., the dataset of ∼0.5 million apks and all extracted features) are made available for replicability. [less ▲]

Chalcopyrite solar cells - state-of-the-art and options for improvement

in Science China: Physics, Mechanics and Astronomy (2022)

Attractor landscapes: a unifying conceptual model for understanding behaviour change across scales of observation

in Health Psychology Review (2022)

Models and theories in behaviour change science are not in short supply, but they almost exclusively pertain to a particular facet of behaviour, such as automaticity or reasoned action, or to a single ... [more ▼]

Models and theories in behaviour change science are not in short supply, but they almost exclusively pertain to a particular facet of behaviour, such as automaticity or reasoned action, or to a single scale of observation such as individuals or communities. We present a highly generalisable conceptual model which is widely used in complex systems research from biology to physics, in an accessible form to behavioural scientists. The proposed model of attractor landscapes can be used to understand human behaviour change on different levels, from individuals to dyads, groups and societies. We use the model as a tool to present neglected ideas in contemporary behaviour change science, such as hysteresis and nonlinearity. The model of attractor landscapes can deepen understanding of well-known features of behaviour change (research), including short-livedness of intervention effects, problematicity of focusing on behavioural initiation while neglecting behavioural maintenance, continuum and stage models of behaviour change understood within a single accommodating framework, and the concept of resilience. We also demonstrate potential methods of analysis and outline avenues for future research. [less ▲]

Quantum friction between metals in the hydrodynamic regime

in Physical Review. A. (2022), 106

We study the phenomenon of quantum friction in a system consisting of a polarizable atom moving at a constant speed parallel to a metallic plate. The metal is described using a charged hydrodynamic model ... [more ▼]

We study the phenomenon of quantum friction in a system consisting of a polarizable atom moving at a constant speed parallel to a metallic plate. The metal is described using a charged hydrodynamic model for the electrons. This model featuring long-range interactions is appropriate for a clean metal in a temperature range where scattering due to Coulomb interactions dominates over the scattering of electron by impurities. We find that a quantum friction force between the atom and the metal surface exists even in the absence of intrinsic damping in the metal, but that it only starts once the velocity of the atom exceeds the effective speed of sound in the metal. We argue that this condition can be fulfilled most easily in metals with nearly empty or nearly filled bands. We make quantitative predictions for the friction force to the second and fourth order in the atomic polarizability, and show that the threshold behavior persists to all orders of the perturbation theory. [less ▲]

A Learning Based Framework for Enhancing Physical Layer Security in Cooperative D2D Network

in Electronics (2022)

Next-generation wireless communication networks demand high spectrum efficiency to serve the requirements of an enormous number of devices over a limited available frequency spectrum. Device-to-device ... [more ▼]

Next-generation wireless communication networks demand high spectrum efficiency to serve the requirements of an enormous number of devices over a limited available frequency spectrum. Device-to-device (D2D) communication with spectrum reuse offers a potential solution to spectrum scarcity. On the other hand, non-orthogonal multiple access (NOMA) as a multiple-access approach has emerged as a key technology to re-use a spectrum among multiple users. A cellular users (CUs) can share their spectrum with D2D users (DUs) and in response, the D2D network can help relay the CU signal to achieve better secrecy from an eavesdropper. Power optimization is known to be a promising technique to enhance system performance in challenging communication environments. This work aimed to enhance the secrecy rate of the CUs where the D2D transmitter (DT) helps in relaying the CU’s message under the amplify and forward (AF) protocol. A power optimization problem is considered under the quality of service constraints in terms of minimum rate requirements at the receivers and maximum power budgets at the transmitters. The problem is a non-convex complex optimization. A deep learning-based solution is proposed and promising results are obtained in terms of the secrecy rate of CU and the rate of D2D users. [less ▲]

Visual SLAM: What Are the Current Trends and What to Expect?

in Sensors (2022), 22(23), 9297

In recent years, Simultaneous Localization and Mapping (SLAM) systems have shown significant performance, accuracy, and efficiency gain. In this regard, Visual Simultaneous Localization and Mapping (VSLAM ... [more ▼]

In recent years, Simultaneous Localization and Mapping (SLAM) systems have shown significant performance, accuracy, and efficiency gain. In this regard, Visual Simultaneous Localization and Mapping (VSLAM) methods refer to the SLAM approaches that employ cameras for pose estimation and map reconstruction and are preferred over Light Detection And Ranging (LiDAR)-based methods due to their lighter weight, lower acquisition costs, and richer environment representation. Hence, several VSLAM approaches have evolved using different camera types (e.g., monocular or stereo), and have been tested on various datasets (e.g., Technische Universität München (TUM) RGB-D or European Robotics Challenge (EuRoC)) and in different conditions (i.e., indoors and outdoors), and employ multiple methodologies to have a better understanding of their surroundings. The mentioned variations have made this topic popular for researchers and have resulted in various methods. In this regard, the primary intent of this paper is to assimilate the wide range of works in VSLAM and present their recent advances, along with discussing the existing challenges and trends. This survey is worthwhile to give a big picture of the current focuses in robotics and VSLAM fields based on the concentrated resolutions and objectives of the state-of-the-art. This paper provides an in-depth literature survey of fifty impactful articles published in the VSLAMs domain. The mentioned manuscripts have been classified by different characteristics, including the novelty domain, objectives, employed algorithms, and semantic level. The paper also discusses the current trends and contemporary directions of VSLAM techniques that may help researchers investigate them. [less ▲]

Provisional Measures and the Risk of Patent Invalidity – “Phoenix Contact” and the German Approach to Interlocutory Injunctions

in Journal of Intellectual Property Law and Practice (2022), 17(11), 962-971

Meatless masculinity: Examining profiles of male veg*n eating motives and their relation to gendered self-concepts

in Current Psychology (2022)

Meat is a food item that is often associated with masculinity. Considering this gender stereotype, research on vegan and vegetarian (veg*n) eating motives has focused on how distinct motives relate to ... [more ▼]

Meat is a food item that is often associated with masculinity. Considering this gender stereotype, research on vegan and vegetarian (veg*n) eating motives has focused on how distinct motives relate to stereotypes of masculinity and femininity. Quantitative studies examining how masculinity and femininity are integrated into the self-concept of these eaters are lacking to date. Moreover, investigators have largely tested the effects of motives in isolation, neglecting the possibility of different motivational profiles that relate differently to gendered self-concepts. The current study adopted a person-centred approach using cluster analysis to identify motivational profiles of self-identified veg*n males, thereby testing whether these profiles differ on dimensions of positive and negative masculinity and femininity. Self-reported data were collected via an online survey among people self-identifying as male and following a vegan or vegetarian dietary pattern (N = 738; 79.8% vegans). A k-means cluster analysis revealed three motivational profiles (n1= 439, 59.5%, ‘equally-balanced’; n2 = 254, 34.4%, ‘ethical-environmental’; n3= 45, 6.1%, ‘moderately-health’). Unique differences emerged in gendered self-concepts tied to all veg*n eating motive profile memberships: Equally-balanced motivated eaters perceived themselves to possess the most positive stereotypical feminine attributes, while moderately-health motivated eaters described themselves with the least of these attributes. Veg*n eaters did not differ on any of the other dimensions of femininity and masculinity. The present study demonstrates that a cluster analysis supplies important information on what combinations of eating motives veg*n males report and how those relate to differences in gendered self-concepts of veg*n eaters. [less ▲]

Intronic enhancers of the human SNCA gene predominantly regulate its expression in brain in vivo.

in Science advances (2022), 8(47), 6324

Evidence from patients with Parkinson's disease (PD) and our previously reported α-synuclein (SNCA) transgenic rat model support the idea that increased SNCA protein is a substantial risk factor of PD ... [more ▼]

Evidence from patients with Parkinson's disease (PD) and our previously reported α-synuclein (SNCA) transgenic rat model support the idea that increased SNCA protein is a substantial risk factor of PD pathogenesis. However, little is known about the transcription control of the human SNCA gene in the brain in vivo. Here, we identified that the DYT6 gene product THAP1 (THAP domain-containing apoptosis-associated protein 1) and its interaction partner CTCF (CCCTC-binding factor) act as transcription regulators of SNCA. THAP1 controls SNCA intronic enhancers' activities, while CTCF regulates its enhancer-promoter loop formation. The SNCA intronic enhancers present neurodevelopment-dependent activities and form enhancer clusters similar to "super-enhancers" in the brain, in which the PD-associated single-nucleotide polymorphisms are enriched. Deletion of the SNCA intronic enhancer clusters prevents the release of paused RNA polymerase II from its promoter and subsequently reduces its expression drastically in the brain, which may provide new therapeutic approaches to prevent its accumulation and thus related neurodegenerative diseases defined as synucleinopathies. [less ▲]

Modular Orders on Defaults in Formal Argumentation

in Journal of Logic and Computation (2022)

Default logic and formal argumentation are paradigmatic methods in the study of nonmonotonic inference. Defeasible information often comes in different strengths stemming from different degrees of ... [more ▼]

Default logic and formal argumentation are paradigmatic methods in the study of nonmonotonic inference. Defeasible information often comes in different strengths stemming from different degrees of reliability in epistemic applications or from varying strengths of authorities issuing norms in deontic applications. In both paradigms methods have been developed to deal with prioritized knowledge bases and normative systems. Questions of comparability of these methods therefore naturally arise. Argumentation theory has been developed with a strong emphasis on unification. It is therefore a desideratum to obtain natural representations of various approaches to (prioritized) default logic within frameworks of structured argumentation, such as ASPIC. Important steps in this direction have been presented in Liao et al. (2016, 2018). In this work we identify and address some problems in earlier translations, we broaden the focus from total to modular orderings of defaults, and we consider non-normal defaults. [less ▲]

Reliability of Spectrum-Efficient Mixed Satellite-Underwater Systems

in IEEE Open Journal of the Communications Society (2022), 3

The combination of radio-frequency (RF) communication and underwater optical wireless communication (UOWC) plays a vital role in the underwater Internet of Things (UIoT). This correspondence proposes a ... [more ▼]

The combination of radio-frequency (RF) communication and underwater optical wireless communication (UOWC) plays a vital role in the underwater Internet of Things (UIoT). This correspondence proposes a dual-hop hybrid satellite underwater system that exploits non-orthogonal multiple access (NOMA) as a spectrum-efficient access technique. The RF link from the satellite to the relay on an oil platform is presumptively subject to a Shadowed-Rician (SR) fading, while the UOWC channels from the relay to the underwater destinations are suggested to follow Exponential-Generalized Gamma (EGG) distributions. The reliability of the system is characterized in terms of both underwater destinations and system outage probabilities (OPs). We derive new closed-form expressions for the OPs under imperfect successive interference cancellation (SIC) conditions. Furthermore, the asymptotic OP and the diversity order (DO) are obtained to learn more about the system’s performance. The results are verified through an extensive representative Monte-Carlo simulation. Also, we investigate the performance against the turbulence of the salty water, air bubbles level (BL), temperature gradients (TG), shadowing parameters, and satellite pointing errors due to satellite motion, even if the beam is pointed at the center of the directive antenna relay, the beam will randomly oscillate. Finally, we contrast our approach with the conventional orthogonal multiple access (OMA) scheme to demonstrate its superiority. [less ▲]

Structural stability despite increased fragmentation: The 2021 county elections in Croatia

in Regional and Federal Studies (2022)

The 2021 county elections in Croatia were the perfect example of political change amidst continuity. Relatively new parties and independent candidates made significant inroads against the dominant players ... [more ▼]

The 2021 county elections in Croatia were the perfect example of political change amidst continuity. Relatively new parties and independent candidates made significant inroads against the dominant players of the center-right and the center-left, most notably in the capital city of Zagreb, where a novel leftist political platform won the elections conclusively. The rise of new and credible alternatives resulted in increased fragmentation of the county assemblies and likely more unstable regional governments in the near future. On the other hand, the party that has dominated Croatian politics since independence, Croatian Democratic Union (HDZ), continued that dominance on the county-level by winning 15 out of 21 offices of county prefects. More important, the determinants of electoral support for the principal political blocs have remained unchanged from the pattern observed in all national elections since the end of Croatia’s War of Independence more than two and a half decades ago. [less ▲]

Overlap of parafermionic zero modes at a finite distance

in Physical Review Research (2022)

Parafermion bound states (PBSs) are generalizations of Majorana bound states (MBSs) and have been predicted to exist as zero-energy eigenstates in proximitized fractional quantum Hall edge states ... [more ▼]

Parafermion bound states (PBSs) are generalizations of Majorana bound states (MBSs) and have been predicted to exist as zero-energy eigenstates in proximitized fractional quantum Hall edge states. Similarly to MBSs, a finite distance between the PBS can split the ground state degeneracy. However, parafermionic modes have a richer exchange statistics than MBSs, so several interaction terms are allowed by the underlying $\mathbb{Z}_{2n}$ symmetry, rendering the effective Hamiltonian governing a pair of PBSs at a finite distance nontrivial. Here, we use a combination of analytical techniques (semiclassical instanton approximation) and numerical techniques (quantum Monte Carlo simulations) to determine the effective coupling Hamiltonian. For this purpose, we go beyond the dilute one-instanton gas approximation and show how finite-size effects can give rise to higher-order parafermion interactions. We find excellent agreement between the analytical results and Monte Carlo simulations. We estimate that these finite-size corrections should be observable in some of the recently proposed experiments to observe PBSs in strongly correlated systems. [less ▲]

Multifunctional Properties of Polyvinylidene-Fluoride-Based Materials: From Energy Harvesting to Energy Storage

in ACS Applied Electronic Materials (2022), 4(11), 54295436

Organic ferroelectrics are increasingly important due to their complementary properties to classical, inorganic ferroelectrics. Flexibility, chemical resistance, scalability, high breakdown fields, and ... [more ▼]

Organic ferroelectrics are increasingly important due to their complementary properties to classical, inorganic ferroelectrics. Flexibility, chemical resistance, scalability, high breakdown fields, and biocompatibility are attractive for many applications like energy harvesting and storage. The most known energy harvesting methods are piezoelectric, pyroelectric, and triboelectric. Here, we apply the well-established material's figures of merit to five polyvinylidene-fluoride-based compositions ranging from ferroelectric to relaxor-like behavior to emphasize the importance of several key material parameters contributing to the maximal power output of energy harvesting devices. Afterward, we discuss the possibility of the same functional material storing the output energy for the development of scalable multifunctional devices. [less ▲]

Multiuser-MISO Precoding under Channel Phase Uncertainty in Satellite Communication Systems

in IEEE Open Journal of Vehicular Technology (2022)

Linear and symbol-level precoding in satellite communications have received increasing research attention thanks to their ability to tackle inter-beam interference, allowing the use of spectral resources ... [more ▼]

Linear and symbol-level precoding in satellite communications have received increasing research attention thanks to their ability to tackle inter-beam interference, allowing the use of spectral resources more efficiently. However, there are still challenges and open questions regarding the implementation of practical precoding systems taking the phase uncertainties in estimating the channel state information into account. This work assesses the impact of phase variations and uncertainties inherent to the satellite communication system operating a precoded forward link. Specifically, we address the inability to measure at the user terminal, the absolute phase rotation introduced by the channel, and the transponder local oscillator phase noise effects on the precoding operations considering the use of frequency division multiplexing in the forward-uplink transmission. We formally demonstrate that the system performance for linear and non-linear precoding operations is not affected by the uncertainty in the phase measurements at the user terminal. Additionally, we show that using a single frequency reference for all the local oscillators at the transponder does not avoid the phase variations related to the frequency division multiplexing in the forward-uplink. This work demonstrates that these phase variations would not affect the system performance for an ideal zero-delay precoding loop. However, this is not feasible in practical scenarios, where the phase noise of the frequency reference at the transponder and the loop delay determine the impact on the system performance. We validate our results by simulations considering three frequency references with different stability levels in a typical GEO satellite system. Our results suggest that practical implementations of multiuser-MISO precoding systems must include a differential phase synchronization loop to compensate for this performance degradation. [less ▲]

Defect Formation and Healing at Grain Boundaries in Lead-Halide Perovskites

in Journal of Materials Chemistry A (2022)

Polycrystalline perovskite solar cells show high power conversion efficiencies despite the presence of grain boundaries (GBs). The benign nature of GBs on the electronic properties and structural ... [more ▼]

Polycrystalline perovskite solar cells show high power conversion efficiencies despite the presence of grain boundaries (GBs). The benign nature of GBs on the electronic properties and structural stability in metal-halide perovskites contradicts their propensity for point defect formation, a controversy that is far from being understood. In this work, we combine ab initio molecular dynamics and density functional theory calculations on the S5[130] GB of cesium lead iodide, CsPbI3, to shed light on the structural and electronic properties of such GBs. Our results present the first evidence of structural healing of GBs driven by the facile migration of iodine ions, resulting in stabilized GB structures with reduced hole trap states and shallow electron trap states by strain-induced Pb–Pb dimers. Drift-diffusion simulations reveal that shallow electron trap states in GB mainly lower open-circuit voltage by enhanced non-radiative recombination. Finally, we observe the spontaneous formation of iodine Frenkel defects with reduced formation energies compared to the perovskite bulk. Overall, our study reveals a controversy of GBs showing a moderate impact on the electronic properties by structural healing but a detrimental impact on the point defect densities, both being connected to the facile migration of iodine ions in GBs. [less ▲]

Qu'est-ce que l'histoire publique ?

in Entre temps (2022)

A Legal Study of the Future of Chinese Infrastructure Development in the Western Balkans in the Light of the EU Rebuilding of Ukraine

in China, Law and Development (2022), (7),

The paper seeks to find out whether the successful EU rebuilding of Ukraine according to European standards can become a game-changer in the competition between Chinese and European infrastructure ... [more ▼]

The paper seeks to find out whether the successful EU rebuilding of Ukraine according to European standards can become a game-changer in the competition between Chinese and European infrastructure development initiatives in the Western Balkans. [less ▲]

Abelianization and fixed point properties of units in integral group rings

in Mathematische Nachrichten (2022)

EFFECTIVE CONTRACTION OF SKINNING MAPS

in Proceedings of the American Mathematical Society, Series B (2022), 9

The Cyber Resilience Act: the EU Commission’s proposal for a horizontal regulation on cybersecurity for products with digital elements. An introduction

in International Cybersecurity Law Review (2022)

The EU Commission presented on 15 September 2022 the proposal for a ‘Regulation on horizontal cybersecurity requirements for products with digital elements amending Regulation (EU) 2019/1020’ (Cyber ... [more ▼]

The EU Commission presented on 15 September 2022 the proposal for a ‘Regulation on horizontal cybersecurity requirements for products with digital elements amending Regulation (EU) 2019/1020’ (Cyber Resilience Act, CRA). This long-awaited piece of legislation would complement EU cybersecurity acquis by laying down horizontal cybersecurity requirements for all products with digital elements. This article sheds light on the ‘horizontal’ character of the CRA proposal by highlighting its main pillars. In particular, the contribution takes into account the new set of obligations placed on economic operators, the conformity assessment procedures as well as the market surveillance framework and the interplay with other legislative initiatives, both in the policy area and outside EU cybersecurity law. Against the backdrop of the sectoral regulatory approach adopted thus far by the Commission vis-à-vis cybersecurity requirements for products, horizontal intervention is needed to ensure legal certainty, avoiding duplicative obligations and further market fragmentation. [less ▲]

Security–Reliability Tradeoff Analysis for SWIPT- and AF-Based IoT Networks With Friendly Jammers

in IEEE Internet of Things Journal (2022), 9(21), 21662-21675

Radio-frequency (RF) energy harvesting (EH) in wireless relaying networks has attracted considerable recent interest, especially for supplying energy to relay nodes in the Internet of Things (IoT) systems ... [more ▼]

Radio-frequency (RF) energy harvesting (EH) in wireless relaying networks has attracted considerable recent interest, especially for supplying energy to relay nodes in the Internet of Things (IoT) systems to assist the information exchange between a source and a destination. Moreover, limited hardware, computational resources, and energy availability of IoT devices have raised various security challenges. To this end, physical-layer security (PLS) has been proposed as an effective alternative to cryptographic methods for providing information security. In this study, we propose a PLS approach for simultaneous wireless information and power transfer (SWIPT)-based half-duplex (HD) amplify-and-forward (AF) relaying systems in the presence of an eavesdropper. Furthermore, we take into account both static power splitting relaying (SPSR) and dynamic power splitting relaying (DPSR) to thoroughly investigate the benefits of each one. To further enhance secure communication, we consider multiple friendly jammers to help prevent wiretapping attacks from the eavesdropper. More specifically, we provide a reliability and security analysis by deriving closed-form expressions of outage probability (OP) and intercept probability (IP), respectively, for both the SPSR and DPSR schemes. Then, simulations are also performed to validate our analysis and the effectiveness of the proposed schemes. Specifically, numerical results illustrate the nontrivial tradeoff between reliability and security of the proposed system. In addition, we conclude from the simulation results that the proposed DPSR scheme outperforms the SPSR-based scheme in terms of OP and IP under the influences of different parameters on system performance. [less ▲]

Ambient intelligence approach: Internet of Things based decision performance analysis for intrusion detection

in Computer Communications (2022), 195

In recent infrastructures, Internet of Things (IoT) have become an important technology for connecting various actuators and sensors over wireless networks. Due to increase in mission-critical ... [more ▼]

In recent infrastructures, Internet of Things (IoT) have become an important technology for connecting various actuators and sensors over wireless networks. Due to increase in mission-critical infrastructures, we make use of these new technologies for reliable communication but their security is always not promising in terms of availability, confidentiality, integrity, and privacy of network services. Users can be compromised and vulnerable by a motivated malicious opponent unless they are not adequately protected by a robust defense. Due to this reason, an ambient intelligence approach for Intrusion Detection System (IDS) is required. In this research, ww proposed Ambient Approach based on Reinforcement Learning Integrated Deep Q-Neural Network (RL-DQN) model for WSNs and IoT in which it leverages the Markov decision process (MDP) formalism to enhance the decision performance in IDS. We deploy RL-DQN-IDS over Edge-cloud intrusion detection infrastructure in which binary attack classification of the network traffic is performed at the edge network while multi-attack classification is performed at the cloud network. To identify intrusions, we use a two-phase process that includes an initial learning phase that relies on RL, followed by a detection and classification phase that relies on DQN. We used four datasets namely UNSW-NB-15, BoTNeTIoT-L01, CICIDS2017 and IoTID20 with a smart house simulation environment configured with WSN and IoT technologies to evaluate performance. Accuracy, precision, and recall were all considered while assessing the dataset under consideration. When compared to five other machine learning models, the RL-DQN model method has demonstrated superior performance. This model outperforms the other five that were tested. [less ▲]

Slow, ordinary and rapid points for Gaussian Wavelets Series and application to Fractional Brownian Motions

in ALEA: Latin American Journal of Probability and Mathematical Statistics (2022), 19

We study the Hölderian regularity of Gaussian wavelets series and show that they display, almost surely, three types of points: slow, ordinary and rapid. In particular, this fact holds for the Fractional ... [more ▼]

We study the Hölderian regularity of Gaussian wavelets series and show that they display, almost surely, three types of points: slow, ordinary and rapid. In particular, this fact holds for the Fractional Brownian Motion. Finally, we remark that the existence of slow points is specific to these functions. [less ▲]

Perceptual Content, Phenomenal Contrasts, and Externalism

in Journal of Philosophy (2022), 119(11), 602-627

According to Sparse views of perceptual content, the phenomenal character of perceptual experience is exhausted by the experiential presentation of ‘low-level’ properties such as (in the case of vision ... [more ▼]

According to Sparse views of perceptual content, the phenomenal character of perceptual experience is exhausted by the experiential presentation of ‘low-level’ properties such as (in the case of vision) shapes, colors, and textures Whereas, according to Rich views of perceptual content, the phenomenal character of perceptual experience can also sometimes involve experiencing ‘high-level’ properties such as natural kinds, artefactual kinds, causal relations, linguistic meanings, and moral properties. An important dialectical tool in the debate between Rich and Sparse theorists is the so-called ‘method of phenomenal contrast’. I explore how this method of phenomenal contrast interacts with the sort of content-externalism made familiar by Putnam. I show that the possibility of Twin Earth style cases places important restrictions on the range of properties that the method of phenomenal contrast could plausibly apply to. Moreover, these restrictions would apply to some paradigmatically low-level properties as well as to some of the frequently advanced high-level properties. I also draw some general lessons about the different ways one might conceive of the relation between phenomenal character and representational content. [less ▲]

Généralisation du recours aux outils de gestion de la liquidité optionnels (swing pricing, droits ajustables et gates,

in Bulletin Joly Bourse (2022)

Vector Perturbation Channel Inversion forSWIPT MU-MISO Systems

in IEEE Wireless Communications Letters (2022)

This letter investigates the employment of vector-perturbation (VP) precoding to convey simultaneously informa-tion and energy in multiple-user multiple-input single-output(MU-MISO) downlink channel. We ... [more ▼]

This letter investigates the employment of vector-perturbation (VP) precoding to convey simultaneously informa-tion and energy in multiple-user multiple-input single-output(MU-MISO) downlink channel. We show that the conventionalVP in addition to the information capacity benefits that providesto linear channel inversion techniques, it enhances the harvestedenergy at the receivers due to the extended symbol constellation.To further boost harvesting performance, a modified VP tech-nique (named VP-EH) is proposed that designs the VP integeroffsets such as to maximize the delivered power. The proposedscheme incorporates an integer least square problem to find theclosest lattice point to a point which is given by a Rayleighquotient optimization problem. Finally, a convex combinationbetween conventional VP and VP-EH is proposed to achieve atrade-off between maximizing information or energy. Theoreticaland simulations results validate that VP is a promising techniqueto simultaneously convey information and energy in MU-MISOsystems. [less ▲]

RIS-Assisted Robust Hybrid Beamforming AgainstSimultaneous Jamming and Eavesdropping Attacks

in IEEE Transactions on Wireless Communications (2022), 21(11), 9212-9231

Wireless communications are increasingly vulnera-ble to simultaneous jamming and eavesdropping attacks due tothe inherent broadcast nature of wireless channels. With thisfocus, due to the potential of ... [more ▼]

Wireless communications are increasingly vulnera-ble to simultaneous jamming and eavesdropping attacks due tothe inherent broadcast nature of wireless channels. With thisfocus, due to the potential of reconfigurable intelligent surface(RIS) in substantially saving power consumption and boostinginformation security, this paper is the first work to investigate theeffect of the RIS-assisted wireless transmitter in improving boththe spectrum efficiency and the security of multi-user cellularnetwork. Specifically, with the imperfect angular channel stateinformation (CSI), we aim to address the worst-case sum ratemaximization problem by jointly designing the receive decoder atthe users, both the digital precoder and the artificial noise (AN)at the base station (BS), and the analog precoder at the RIS, whilemeeting the minimum achievable rate constraint, the maximumwiretap rate requirement, and the maximum power constraint.To address the non-convexity of the formulated problem, we firstpropose an alternative optimization (AO) method to obtain anefficient solution. In particular, a heuristic scheme is proposedto convert the imperfect angular CSI into a robust one andfacilitate the developing a closed-form solution to the receivedecoder. Then, after reformulating the original problem into atractable one by exploiting the majorization-minimization (MM)method, the digital precoder and AN can be addressed by thequadratically constrained quadratic programming (QCQP), andthe RIS-aided analog precoder is solved by the proposed pricemechanism-based Riemannian manifold optimization (RMO).To further reduce the computational complexity of the pro-posed AO method and gain more insights, we develop a low-complexity monotonic optimization algorithm combined with thedual method (MO-dual) to identify the closed-form solution.Numerical simulations using realistic RIS and communicationmodels demonstrate the superiority and validity of our proposedschemes over the existing benchmark schemes. [less ▲]

Bibliothéconomie et pratiques de l’écrit à Saint-Maximin de Trèves du XIIIe au XVIe siècle : Premiers regards sur la base du « grand légendier » et d’autres manuscrits hagiographiques

in Questes: Revue pluridisciplinaire d'études médiévales (2022), 44

Adapting to Dynamic LEO-B5G Systems: Meta-Critic Learning Based Efficient Resource Scheduling

in IEEE Transactions on Wireless Communications (2022), 21(11), 9582-9595

Low earth orbit (LEO) satellite-assisted communications have been considered as one of the key elements in beyond 5G systems to provide wide coverage and cost-efficient data services. Such dynamic space ... [more ▼]

Low earth orbit (LEO) satellite-assisted communications have been considered as one of the key elements in beyond 5G systems to provide wide coverage and cost-efficient data services. Such dynamic space-terrestrial topologies impose an exponential increase in the degrees of freedom in network management. In this paper, we address two practical issues for an over-loaded LEO-terrestrial system. The first challenge is how to efficiently schedule resources to serve a massive number of connected users, such that more data and users can be delivered/served. The second challenge is how to make the algorithmic solution more resilient in adapting to dynamic wireless environments. We first propose an iterative suboptimal algorithm to provide an offline benchmark. To adapt to unforeseen variations, we propose an enhanced meta-critic learning algorithm (EMCL), where a hybrid neural network for parameterization and the Wolpertinger policy for action mapping are designed in EMCL. The results demonstrate EMCL’s effectiveness and fast-response capabilities in over-loaded systems and in adapting to dynamic environments compare to previous actor-critic and meta-learning methods. [less ▲]

ReSQ: Reinforcement Learning-Based Queue Allocation in Software-Defined Queuing Framework

in Journal of Networking and Network Applications (2022), 2(4), 143152

With the evolution of 5G networks, the demand for Ultra-Reliable Low Latency Communications (URLLC) services is increasing. Software-Defined Networking (SDN) offers flexible network management to ... [more ▼]

With the evolution of 5G networks, the demand for Ultra-Reliable Low Latency Communications (URLLC) services is increasing. Software-Defined Networking (SDN) offers flexible network management to prioritize URLLC services coexisting with best-effort traffic. Utilizing the network programmability feature of SDN, Software-Defined Queueing (SDQ) framework selects the optimal output port queue on forwarding devices and routing path for incoming traffic flows to provide deterministic Quality of Service (QoS) support required for URLLC traffic. However, in the existing SDQ framework, the selections of optimal queue and path are done manually by observing the traffic type of each incoming flow, the available bandwidth of each potential routing path, and the status of output port queues of each forwarding device on each potential routing path. The static allocations of path and queue for each flow are inefficient to provide a deterministic QoS guarantee for a high volume of incoming traffic which is typical in 5G networks. The limited buffer availability on the forwarding devices is another constraint regarding optimal queue allocation that ensures an end-to-end (E2E) delay guarantee. To address these challenges, in this paper, we extend the SDQ framework by automating queue management with a reinforcement learning (RL)-based approach. The proposed queue management approach considers diverse QoS demands as well as a limited buffer on the forwarding devices and performs prioritized queue allocation. Our approach also includes a hash-based flow grouping to handle a high volume of traffic having diverse latency demands and a path selection mechanism based on available bandwidth and hop count. The simulation result shows that the proposed scheme ReSQ reduces the QoS violation ratio by 10.45% as compared to the baseline scheme that selects queues randomly. [less ▲]

Making Elections Work: Accountability with Selection and Control

in American Economic Journal. Microeconomics (2022), 14(4), 616-644

We study the limits of dynamic electoral accountability when voters are uncertain about politicians’ characteristics (adverse selection) and their actions (moral hazard). Existing work argues that voters ... [more ▼]

We study the limits of dynamic electoral accountability when voters are uncertain about politicians’ characteristics (adverse selection) and their actions (moral hazard). Existing work argues that voters cannot achieve their first-best payoff. This is attributed to inherent deficiencies of the electoral contract, including voters’ inability to pre-commit, and the restriction to a binary retention-replacement decision. We provide conditions under which, despite these constraints, voters can obtain arbitrarily close to the first-best payoff in an equilibrium of the electoral interaction. Our paper resolves that there need not be a trade-off between selection and control. [less ▲]

Spectral Efficiency Analysis of Hybrid Relay-Reflecting Intelligent Surface-Assisted Cell-Free Massive MIMO Systems

in IEEE Transactions on Wireless Communications (2022)

A cell-free (CF) massive multiple-input-multiple-output (mMIMO) system can provide uniform spectral efficiency (SE) with simple signal processing. On the other hand, a recently introduced technology ... [more ▼]

A cell-free (CF) massive multiple-input-multiple-output (mMIMO) system can provide uniform spectral efficiency (SE) with simple signal processing. On the other hand, a recently introduced technology called hybrid relay-reflecting intelligent surface (HR-RIS) can customize the physical propagation environment by simultaneously reflecting and amplifying radio waves in preferred directions. Thus, it is natural that incorporating HR-RIS into CF mMIMO can be a symbiotic convergence of these two technologies for future wireless communications. This motivates us to consider an HR-RIS-aided CF mMIMO system to utilize their combined benefits. We first model the uplink/downlink channels and derive the minimum-mean-square-error estimate of the effective channels. We then present a comprehensive analysis of SE performance of the considered system. Specifically, we derive closed-form expressions for the uplink and downlink SE. The results reveal important observations on the performance gains achieved by HR-RISs compared to conventional systems. The presented analytical results are also valid for conventional CF mMIMO systems and those aided by passive reconfigurable intelligent surfaces. Such results play an important role in designing new transmission strategies and optimizing HR-RIS-aided CF mMIMO systems. Finally, we provide extensive numerical results to verify the analytical derivations and the effectiveness of the proposed system design under various settings. [less ▲]

Mezinárodní soft law jako koncept v judikatuře správních soudů

in Jurisprudence (2022), (5), 1-10

International soft law as a concept encompasses a large number of diverse international acts that are not legally binding but still are capable to produce legal effects. For national courts, international ... [more ▼]

International soft law as a concept encompasses a large number of diverse international acts that are not legally binding but still are capable to produce legal effects. For national courts, international soft law presents a foreign element because it is adopted beyond the state and it defies the traditional binary concept of law, according to which legal norms are binding, otherwise they are not law. Nevertheless, this foreign element finds its way into the decision-making of Czech administrative courts. The article maps how and in which situations the administrative courts work with the concept of soft law and what consequences they draw from soft law. [less ▲]

Betting Against Noisy Beta

in Journal of Finance and Data Science (2022), 8(-), 55-68

Individualised prediction of drug resistance and seizure recurrence after medication withdrawal in people with juvenile myoclonic epilepsy: A systematic review and individual participant data meta-analysis

in eClinicalMedicine (2022)

Summary Background A third of people with juvenile myoclonic epilepsy (JME) are drug-resistant. Three-quarters have a seizure relapse when attempting to withdraw anti-seizure medication (ASM) after ... [more ▼]

Summary Background A third of people with juvenile myoclonic epilepsy (JME) are drug-resistant. Three-quarters have a seizure relapse when attempting to withdraw anti-seizure medication (ASM) after achieving seizure-freedom. It is currently impossible to predict who is likely to become drug-resistant and safely withdraw treatment. We aimed to identify predictors of drug resistance and seizure recurrence to allow for individualised prediction of treatment outcomes in people with JME. Methods We performed an individual participant data (IPD) meta-analysis based on a systematic search in EMBASE and PubMed – last updated on March 11, 2021 – including prospective and retrospective observational studies reporting on treatment outcomes of people diagnosed with JME and available seizure outcome data after a minimum one-year follow-up. We invited authors to share standardised IPD to identify predictors of drug resistance using multivariable logistic regression. We excluded pseudo-resistant individuals. A subset who attempted to withdraw ASM was included in a multivariable proportional hazards analysis on seizure recurrence after ASM withdrawal. The study was registered at the Open Science Framework (OSF; https://osf.io/b9zjc/). Findings  368) was predicted by an earlier age at the start of withdrawal, shorter seizure-free interval and more currently used ASMs, resulting in an average internal-external cross-validation concordance-statistic of 0·70 (95%CI 0·68–0·73). Interpretation We were able to predict and validate clinically relevant personalised treatment outcomes for people with JME. Individualised predictions are accessible as nomograms and web-based tools. Funding MING fonds. [less ▲]

A Survey on Semantic Communications for Intelligent Wireless Networks

in Wireless Personal Communications (2022)

Research on intelligent wireless network aims at the development of a human society which is ubiquitous and mobile, simultaneously providing solutions to the coverage, capacity, and computing issues ... [more ▼]

Research on intelligent wireless network aims at the development of a human society which is ubiquitous and mobile, simultaneously providing solutions to the coverage, capacity, and computing issues. These networks will focus on provisioning intelligent use-cases through higher data-rates over the millimeter waves and the Tera-Hertz frequency. However, at such high frequencies, multiple non-desired phenomena such as, atmospheric absorption and blocking occur which create a bottleneck owing to resource scarcity. Hence, existing trend of exactly reproducing transmitted data at the receiver will result in a constant need for higher bandwidth. A possible solution to such a challenge lies in semantic communications which focuses on meaning (relevance or context) of the received data. This article presents a detailed survey on the recent technological trends in regard to semantic communications for intelligent wireless networks. Initially, the article focuses on the semantic communications architecture including the model, and source and channel coding. Next, cross-layer interaction, and various goal-oriented communication applications are detailed. Further, overall semantic communications trends are presented following which, the key challenges and issues are detailed. Lastly, this survey article is an attempt to significantly contribute towards initiating future research in the area of semantic communications for the intelligent wireless networks. [less ▲]

An in-depth investigation of the performance characteristics of Hyperledger Fabric

in Computers and Industrial Engineering (2022), 173

Private permissioned blockchains are deployed in ever greater numbers to facilitate cross-organizational processes in various industries, particularly in supply chain management. One popular example of ... [more ▼]

Private permissioned blockchains are deployed in ever greater numbers to facilitate cross-organizational processes in various industries, particularly in supply chain management. One popular example of this trend is Hyperledger Fabric. Compared to public permissionless blockchains, it promises improved performance and provides certain features that address key requirements of enterprises. However, also permissioned blockchains are still not as scalable as centralized systems, and due to the scarcity of theoretical results and empirical data, their real-world performance cannot be predicted with the necessary precision. We intend to address this issue by conducting an in-depth performance analysis of Hyperledger Fabric. The paper presents a detailed compilation of various performance characteristics using an enhanced version of the Distributed Ledger Performance Scan (DLPS). Researchers and practitioners alike can use the various performance properties identified and discussed as guidelines to better configure and implement their Hyperledger Fabric network. Likewise, they are encouraged to use the DLPS framework to conduct their measurements. [less ▲]

Thickness and relative hyperbolicity for graphs of multicurves

in Journal of Topology (2022), 15(4), 2317-2351

We prove that any graph of multicurves satisfying certain natural properties is either hyperbolic, relatively hyperbolic, or thick. Further, this geometric characterization is determined by the set of ... [more ▼]

We prove that any graph of multicurves satisfying certain natural properties is either hyperbolic, relatively hyperbolic, or thick. Further, this geometric characterization is determined by the set of subsurfaces that intersect every vertex of the graph. This extends previously established results for the pants graph and the separating curve graph to a broad family of graphs associated to surfaces. [less ▲]

EMPTY

in Empty (2022)